Stinky stuff

Alicia Ybarra has lived behind the city's water treatment plant for 33 years, but she's never gotten used to the smell that occasionally wafts through her 39th Street block.

"Really it's a smell between oil and sewer," Ybarra said while watering her azaleas Wednesday. "It's really sour."

Jo Green, who lives with her niece off Merrill Avenue, laughed when asked to describe it.

"It's just a terrible smell," she said. "It smells like sewage."

Both women said they've found ways to deal, but a consultant study approved by the City Council Tuesday aims to give their noses some permanent relief.

The $32,000 consultant agreement with Fort Worth-based Alan Plummer Associates Inc. will come up with a plan for more efficient handling of the water treatment plant's sludge stockpile, the cause behind the smell that seeps from the facility periodically. 

"The good thing about Alan Plummer is they're very familiar with our plant," said Debbie McReynolds, utilities director. "This allows them to hit the ground running."

The process that produces sludge is pretty complex, and it starts with water piped from Lake Ivie, the city's main water provider.

The lake water arrives at the plant untreated, so a series of intricate machinery and filters work non-stop to get rid of soil and any other materials before it's disinfected and sent out to homes and businesses. The materials that get filtered out are collectively known as sludge, a stinky, mud-like substance that is eventually hauled off to Odessa's landfill.

But before it gets hauled off, the sludge has to be dried out, and that's where the smell comes into play.

Most of the sludge is collected in the plant's settling basins, where lake water flows after it's treated with aluminum sulfate to help particulate matter settle to the bottom of the tank. Automated sludge removers move along the bottom of the settling basins to collect the stinky stuff, and then it's piped into the plant's drying lagoons.

The sludge will sit in these drying lagoons before it can be transported to the landfill, but sometimes water can be trapped underneath its top layer.

McReynolds said plant workers have to "turn" the sludge every now and then to facilitate the drying process, and that's when residents start getting nasty whiffs.

"It stinks," said Merrill Avenue resident Jessica Flores. "I don't really come out too much 'cause it's gross."

Because the automated sludge drudgers are constantly depositing into the drying lagoons, it's hard for the sun to do its work quickly, so the consultant study will look at ways to speed up this process.

Alan Plummer's James Naylor, project manager for the study, said his team will explore four options to alleviate Odessa's sludge problem.

The first is installing high-rate drying beds to replace the plant's drying lagoons. These would have a filtering layer to set the sludge on top of, allowing water to drip through the bottom while the sun works to dry the sludge on top. 

The second is diverting all sludge to the Derrington wastewater treatment plant through the city's sewer system, effectively taking it completely offsite. The third would look at what's called mechanical dewatering. This method uses chemicals and centrifuges or presses to get the water out of sludge immediately, making it ready for the landfill much sooner than traditional drying methods.

 The fourth option, one Naylor labeled as an "option of last resort," would leave the sludge treatment process as it is now.

The study should take about 120 days, and since Alan Plummer won't be using any subcontractors, Naylor said the study's cost doesn't have any potential to rise.

"My feet are held to the fire on that one," he said.

AT A GLANCE:

>> What: Water treatment plant study.

>> Who: Conducted by Alan Plummer Associates, a Fort Worth-based public utility consultant.

>> Why: Will look at the best way to deal with water treatment plant sludge.

>> Cost: $32,000.

>> How long: Study should last 120 days.